I. Field of the Invention
The present invention relates generally to a disposal system for unused or expired medications. More particularly, the invention involves the use of binding agents to immobilize and prevent release of medications into the body of an abuser, or to the environment.
II. Related Art
The temptation and potential for prescription drug abuse by ingestion, injection, etc., and particularly, of narcotics and other controlled substances is well known. This widespread abuse issue is exemplified by the current problems associated with morphine, oxycontin, fentanyl, and many others.
Unfortunately, problems associated with medications are not limited to abusable narcotics. According to a recent investigative report by the Associated Press, Americans flush 250 million pounds of pharmaceuticals down the drain every year (reference: Living on Earth.org online interview with the EPA, Oct. 3, 2008). Further, this has resulted in contamination of the drinking water supply of numerous major cities throughout the U.S. (reference Air Force Print News Today, Mar. 24, 2008).
These contaminants pose risk to the environment; affecting people, fish and wildlife. Potential problems include abnormal physiological processes, reproductive impairment, increased evidence of cancer, and development of anti-microbial resistant organisms (reference: Kansas Dept of Health and Environment, Mar. 22, 2007).
A significant source of pharmaceutical environmental contamination lies with disposal of unused or expired medications (reference eMedicineHealth Mar. 21, 2008). Historically, these medications are flushed down the toilet or thrown into the trash, with a likely outcome that they will eventually end up in groundwater supplies. The only medications that the FDA condones flushing down the toilet are controlled substances with abuse potential. Thus, many people are faced with a dilemma, how to dispose of unused and expired medications?
Of particular interest is the potential for abuse or environmental release associated with medications contained in transdermal patch technology. Unfortunately, with transdermal patches significant amounts of drug compound remain in the patches after patients have worn them for the prescribed period of time. The need for this excess amount of drug is well known; it is required to insure an adequate driving force in the transdermal application for the full wear time period. For example, in a published test of Duragesic® (trademark of Johnson & Johnson) patches worn for the full 72-hour wear period, 28-84.4% of the original loading of fentanyl still remained in the patches. The authors of the study concluded that the residual dosage represented amounts sufficient for abuse and misuse and was even potentially lethal. (Marquardt et al, Ann Pharmacother, 1995, 29:969-71).
Upon recognizing the need to deactivate residual fentanyl following the wearing of transdermal patches, researchers in a published study recommended that used patches be immersed in heated hydrochloric or sulfuric acid (Zambaux et. al. Ann Pharm Fr 2000, 58: 176-179). This method was found to deactivate the residual Fentanyl by a hydrolysis chemical reaction. A significant disadvantage of this method is that it requires the handling of very hazardous materials and procedures not common to most users of prescription medications.
Another approach to the reduction of abuse potential in transdermal drug administration is found in U.S. Pat. No. 5,236,714. That document discloses the combination of the drug with a co-formulated antagonist agent that is present in a form not releasable in the dosage form, but one which releases to prevent abuse of the composition by certain other routes of administration. Thus, the co-formulated antagonist does not penetrate transdermally, but would be co-extracted during an attempt to extract the abusable material as by using solvents or by removing and ingesting the combination. One disadvantage to this approach resides in the shelf-life complications associated with co-formulation of two active pharmaceutical ingredients in a transdermal patch. Another significant limitation to this approach is that a used patch can still be abused with transdermal wear. Finally, this approach does not address environment impact issues.
In U.S. Pat. No. 5,804,215 (“Cubbage”), a disposal system for a transdermal patch is described having a pouch which serves as an encapsulation system. One limitation to this approach is that it can be defeated, and abusable substance accessed, by a breach of the encapsulent material. In U.S. application publication 2004/0146547 (“Marcenyac”)a disposal system is described where an article used to contain a transdermal patch can further include a detection and/or inactivation agent that is released when the agent or dosage form is misused. Detection agents include indelible dyes. Examples of inactivating agents include opioid receptors that bind the residual opioid into an insoluble ligand-receptor complex, opioid receptor antagonists, physical sequestering agents, or non-opioids with distressing or dysphoric properties. There are numerous limitations associated with this approach. For example, many inactivation agents are specific for a particular drug compound and will be ineffective when used with other drugs; many approaches are limited to abuse protection, and compound environmental discharge issues by inclusion of additional medically active compounds. Further, film (solid) forms of the inactivating agent layer will contact only the surface content of the medication. If the patch or medication reservoir is “dry”, medications contained beneath the surface layer will not contact the inactivation agent. A further significant limitation to this approach is that the detection and/or inactivating agents are released only when the article is misused, and therefore are not activated when the article is properly used and discarded.
Environmental and abuse problems are certainly not limited to medications in transdermal patch form. In fact, medications are most often in oral pill or liquid solution form. Once unused or expired oral medications are discarded, these medications may be recovered from the trash and abused by others. In addition, compounds from large amounts of discarded medications are inevitably released to the ground water supply over time.
Therefore, there remains a need for a more universal, safe, and more effective means of preventing abuse and/or environmental contamination of unused or expired medications in a variety of forms including pill, liquid and transdermal patch forms.